Share-Based Payments (Summary Of Stock-Settled SARs Activity Under The 2007 Plan) (Detail) (USD $)	12 Months Ended
Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised, Shares	22,342
Stock-Settled SARs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding	630,947
Granted, Shares	493,518
Exercised, Shares	(13,397)
Expired or forfeited, Shares	(183,843)
Shares, Outstanding	927,225
Vested or expected to vest as of year end, Shares	785,833
Exercisable at end of year, Shares	201,645
Weighted-Average Exercise Price, Outstanding	28.22
Granted, Weighted-Average Exercise Price	32.18
Exercised, Weighted-Average Exercise Price	28.38
Expired or forfeited, Weighted-Average Exercise Price	28.97
Weighted-Average Exercise Price, Outstanding	30.18
Vested or expected to vest as of year end, Weighted-Average Exercise Price	37.41
Exercisable at end of year, Weighted-Average Exercise Price	28.53

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

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Weighted average price of options that were either forfeited or expired.

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Net number of share options (or share units) granted during the period.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Number of share options (or share units) exercised during the current period.

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